Ubuntu Split DNS walk through (w/ddns)

I'm looking for some feedback on where I could host this other than at the PBWiki site. Anyone who would like is free to make edits which would improve it.

Also, I haven't installed Zimbra on top of it yet. My goal is a zimbra install behind a home firewall, with dyndns & mailhop services. (I had this working with Exchange...) Any input or desire to help with a second wiki section?